1. Technical Field
Embodiments described in this specification relates to a confocal optical scanner that scans a sample with illumination light to obtain a confocal image and to a confocal microscope equipped with such a confocal optical scanner.
2. Related Art
Heretofore, a confocal microscope has been used in various kinds of observations. The confocal microscope is provided with a confocal optical scanner for scanning a sample with illumination light. In particular, the confocal optical scanner employs laser light irradiation to scan a sample in which a fluorescent material (e.g., fluorescent pigment or fluorescent protein) is incorporated. The laser light (irradiation light) excites the fluorescent material in the sample to generate fluorescence from the sample. Therefore, the sample can be observed by detection of the fluorescence. An example of such a confocal optical scanner used in a confocal microscope is disclosed in JP-A-2011-85759.
This patent document discloses a so-called Nipkow disk type confocal optical scanner. The confocal optical scanner includes a pinhole disk and a condenser disk, where confocal openings (pinholes) are formed in the pinhole disk. When scanning a sample to acquire a confocal image, the confocal optical scanner rotates the pinhole disk and the condenser disk integrally with each other as a single pinhole unit. Here, the confocal optical scanner includes two different pinhole units, that is, a small-diameter pinhole unit having small-diameter pinholes and a large-diameter pinhole unit having large-diameter pinholes, which can be replaced with each other as needed.
The confocal optical scanner disclosed in the above patent document includes a direct-acting slider that is able to move both the small-diameter pinhole unit and the large-diameter pinhole unit. In other words, the confocal optical scanner can be controlled to select one of the pinhole units so that the selected one has a pinhole diameter appropriate for the numerical aperture (NA) of an objective lens. Therefore, optical conditions of a confocal microscope, such as resolution and brightness of a confocal image, can be optimized according to optical characteristics, such as numerical aperture (NA) and magnification ratio of an objective lens.